Effects of nitrogen-doping configurations with vacancies on conductivity in graphene

TL;DR

This study explores how different nitrogen-doping configurations and vacancies affect the electrical conductivity of graphene, revealing that ordered dopants and vacancies can significantly enhance conductivity and alter electron-hole symmetry.

Contribution

It provides a detailed numerical analysis of how various nitrogen-doping configurations and vacancies influence graphene's conductivity, including effects of dopant correlation and ordering.

Findings

Conductivity increases up to several times with correlated N dopants.

Ordered N dopants can enhance conductivity by tens of times.

Vacancies and dopant ordering suppress electron-hole asymmetry.

Abstract

We investigate electronic transport in the nitrogen-doped graphene containing different configurations of point defects: singly or doubly substituting N atoms and nitrogen-vacancy complexes. The results are numerically obtained using the quantum-mechanical Kubo-Greenwood formalism. Nitrogen substitutions in graphene lattice are modelled by the scattering potential adopted from the independent self-consistent ab initio calculations. Variety of quantitative and qualitative changes in the conductivity behaviour are revealed for both graphite- and pyridine-type N defects in graphene. For the most common graphite-like configurations in the N-doped graphene, we also consider cases of correlation and ordering of substitutional N atoms. The conductivity is found to be enhanced up to several times for correlated N dopants and tens times for ordered ones as compared to the cases of their random distributions. The presence of vacancies in the complex defects as well as ordering of N dopants suppresses the electron-hole asymmetry of the conductivity in graphene.